Machine for cutting rubber grommets



Jan. 17, 1956 E. N. BRODEN MACHINE FOR CUTTING RUBBER GROMMETS 2 Sheets-Sheet 1 Filed June 2 1951 vw 8% mm INVENTOR. EDW/N N. BRODE/V BY I 3 ATTORNEYS Jan. 17, 1956 E: N. BRODEN I MACHINE FOR CUTTING RUBBEQ R GROMMETS 2 Sheets-Sheet 2 Filed June 2, 1951 m wot INVENTOR. EDW/IV IV. BRODE/V ATTORNEYS United States Patent MACHHVE FOR-CUTTING RUBBER GROMMETS Edwin N. Broden, Assonet, Mass, assignor to The Firestone Tire & Rubber Company, Akron, Ohio, a corporation of Ohio Application June 2, 1951, Serial No. 229,617

Claims. (Cl. 164-38) This invention relates to a machine for cutting rubber grommets. Grommets of the type considered are annular in form, with cylindrical inner aperture and a generally rounded, outer surface having a central groove running peripherally of the grommet. Heretofore, these have been formed and cured in individual mold sections. It has been found that production is greatly increased and production costs lowered if the material is extruded, with proper cross section, wound into the form of a helix and cured while in this form, and the individual grommets formed by a slit along one side of the helix parallel to its axis. The present invention relates to a machine for cutting the helix.

It is therefore an object of the invention to provide for rapid cutting of slits along a helix of rubber-like material.

Further objects are to provide a machine to accomplish the foregoing which is simple of structure, low in cost, and easy of operation and maintenance.

These objects are attained by the invention, a preferred form of which is described in the following specification and illustrated in the drawings, in which:

Fig. 1 is an elevational view of the cutter,

Fig. 2 is a top plan view of Fig. 1,

Fig. 3 is an end view of Fig. l, as seen from the left thereof, on the line 3 3,

Fig. 4 is a sectional view taken on the line 44 of Pig. 2,

Fig. 5 is a plan view of an individual grommet after cutting,

Fig. 6 is a sectional view taken along the line6-6 of Fig. 5, and

Fig. 7 is a fragmentary view showing a detail from Fig. 4 as seen from above.

Referring to the drawings by characters of reference, there is shown a tube 1, secured to a pair of standards 2, 3, which are secured to a suitable support 4 by screws 6. A rod 7 of considerably smaller diameter than the inner diameter of tube 1 is positioned axially of the tube, being supported, cantilever-fashion by lodgment in an element 8 suitably secured to a collar 9, which is held in place on tube 1 at the left end thereof as by a set screw 11.

A second collar 12 spaced to the right of collar 9, is also secured to tube 1 as by a set screw 13, and includes a pair of jutting, horizontal arms 14, 16, constituting clamps for holding a knife 17 in generally vertical position, bolts 18 being provided for the clamping action.

Tube 1 has a cutaway portion 19 in its upper side, through which knife 17 extends, and the point of the cutable in piston fashion in tube 1 and with its bore received on rod 7. A knob 28 is provided for hand manipulation, and a stop collar 29 limits inward movement of the pusher to a position short of contact of the latter with the knife blade. Whatever convolutions at the end of the helix have not been cut will be moved through the tube by the next helix placed in tube 1.

After the respective slits are made, they are opened in passing along plow-shaped element 23 so that they may pass around rod 7 and fall into a receptacle.

As seen in Fig. 6, the grommets have a channel 31 for engagement with the rim of a hole in a metal wall, as in automobile bodies, and are intended to insulate electric wires from such holes. As cut by the machine shown, the several, separated convolutions of the helix retain their helical form and it has been found in practice that this form renders installation easier, since the grommets may be lodged by a screwing action.

While a certain preferred embodiment has been shown and described, the invention is not limited thereby, since various modifications may be resorted to without departing from the spirit or scope of the invention.

What is claimed is:

1. For slitting a helix of rubber-like material into grommets, a tube, a cantilever arm extending through said tube and spaced from the interior surface to receive said helix, said tube extending substantially the entire length of said arm, a knife mounted in said tube and having a cutting edge extending in a generally radial direction at least as far as the surface of said arm, means mounted in said tube and adapted to advance said helix along said arm through said tube and against the edge of said knife to sever said helix into grommets, and a plow-shaped element aligned with said knife and mounted on the delivery side thereof, said element adapted to expand said grommets and permit said grommets to escape from the arm.

2. For slitting a helix of rubber-like material into grommets, a tube, a cantilever arm extending through said tube and spaced from the interior surface to receive said helix, said tube extending substantially the entire length of said arm, a knife mounted in said tube and having a cutting edge extending in a generally radial direction at least as far as the surface of said arm, means mounted in said tube and adapted to advance said helix along said arm through said tube and against the edge of said knife to sever said helix into grommets, and means mounted in said tube on the delivery side of the knife and adapted to expand said severed helix and allow portions thereof to escape from said arm and drop from the end of said tube.

3. For slitting a helix of rubber-like material into grommets, a tube, a cantilever arm having a recess in its surface extending through said tube and spaced from the interior surface to receive said helix, said tube extending substantially the entire length of said arm, a knife mounted in said tube with one end in said recess and having a cutting edge extending in a general radial direction at least as far as the surface of said arm, means mounted in said tube and adapted to advance said helix along said arm through said tube and against the edge of said knife to sever said helix into grommets, and means mounted in said tube on the delivery side of the knife and adapted to expand said severed helix and allow portions thereof to escape from said arm ting edge 21 of the knife is received in a recess 22 of rod .7;

Element 8, holding rod 7, is spaced somewhat from the 9 end of tube 1 and, in this region, rod 7 has a plow-shaped element 23 (seen in top plan view in Fig. 7) fixed to its top surface for a purpose presently to be explained,

Rod 7 is of a size to snugly receive the helix mil/which in turn is snugly received in tube 1. The slit 26'i s made merely by moving the helix convolutions successively past the knife blade. Such movement of the helix is effected by a removable pusher element 27 of tubular form ,'mov- ,and drop from the end of said tube. 4. For slitting a helix of rubber-like material into grommets, a tube having an opening in its walls, a cantilever ing a smaller outside diameter than the diameter of said first tube and having a larger inside diameter than the diameter of said arm fitting into said first tube and adapted for reciprocating motion in said first tube whereby said helix is advanced against said knife to cut said helix into grommets, and a plow-shaped element aligned with said knife on the delivery side thereof and adapted to expand the grommets to allow said grommets to escape from said arm.

5. F or slitting a helix of rubber-like material into grommets, a tube having an opening in its Walls, a cantilever arm extending through said tube and spaced from the interior surface thereof to receive said helix, said tube extending substantially the entire length of said arm, a knife extending through the opening in said tube and having a cutting edge extending in a generally radial direction at least as far as the surface of said arm, a second tube having a smaller outside diameter than the inside diameter of said first tube and having a larger inside diameter than the diameter of said arm fitting into said first tube and adapted for reciprocating motion in said first tube whereby References Cited in the file of this patent UNITED STATES PATENTS 505,071 Sterling Sept. 12, 1893 541,996 Fox July 2, 1895 1,054,143 Plost Feb. 25, 1913 1,801,363 Mueller Apr. 21, 1931 2,137,697 Pierce Nov. 22, 1938 2,279,211 Thomas Apr. 7, 1942 2,413,715 Kemp Jan. 7, 1947 2,428,540 Babbitt Oct. 7, 1947 2,452,431 Collins Oct. 26, 1948 2,568,775 Stull Sept. 25, 1951 2,660,759 Davis et a1. Dec. 1, 1953 

